quality as "the degree to which a set of inherent characteristics fulfills requirements" (ISO/IEC 9001).
* The product perspective implies that quality can be appreciated by measuring the inherent characteristics of the product.
* The final perspective of quality is value-based. This perspective recognizes that the different perspectives of quality may have different importance, or value, to various stakeholders.

Tom DeMarco has proposed that "a product's quality is a function of how much